Abstract
BACKGROUND: Bilateral testicular neoplasia is rare, with an incidence ranging from 1 to 5%. Long-term survival has improved in recent years due to advanced diagnostic approaches and new therapeutic methods that are highly effective against germ cell tumors. CASE PRESENTATION: We present the case of a patient with a primary seminomatous testicular tumor, who developed a contralateral metastasis and a subsequent metachronous tumor following chemotherapy and consolidation radiotherapy treatment. CONCLUSIONS: Strict follow-up, including physical examination and ultrasound examination of the contralateral testis, enabled early diagnosis of the second tumor, giving the patient a high likelihood of a definitive cure.